Abrasion resistance tester



Feb. 5, 1952 D. M. PACKER 2,584,156

ABRASION RESISTANCE TESTER Filed May 19. 1949 3 Sheets-Sheet l INVENTOR DONALD M. PACKER ATTORNEY Feb. 5, 1952 PACKER 2,584,156

ABRASION RESISTANCE TESTER Filed May 19. 1949 a Sheets-Sheet 2 FIG.

INVENTOR DONALD M. PAOKER BY I M ATTORNEY 1952 0. M. PACKER ABRASION RESISTANCE TESTER 3 Shets-S'neet Filed May 19, 1949 INVENTOR DONALD M. PAGKER ATTORNEY Patented Feb. 5, 1952 UNITED STATE S 2,584,156

ABEASION RESISTANCE TESTE Donald Packer, Alexandria, Va.

Application May 19, 1949., Serial si n 6 claims. (01.. 73 Granted under the act of Mach 3, 1883, as.

amended April30, 1928; 370. Q- Gr, 7.57)

The present invention relates to an abrading or polishing apparatus, and more particularly to such an'apparatus for testing the abrasion resistance of surfaces, surface finishes, and the like by applying a circular abrading or rubbing action thereto.

Q-ne object of the present invention is to provide an apparatus which is compact, simple of structure, and convenient in operation for testing'the abrasion resistance of surfaces and the like.

h r Qbi ct s, o cc mpli h the o eg n by applying a cireularrubbing action to said sur: faces by means of an abradi-ng surface or lap.

Another object is to provide an apparatus which will accomplish the foregoing and will facilfitate the application of difierent pressures by the lap to the surface being tested.

A further object of the present invention is to provide an apparatus of the above character which will record the cycles made by the abrading surface or lap against the surface being tested.

In general, the apparatus consists of a power driven cam having an accentric opening therein for receiving the shaft of the abrading unit which is free to rotate and slide axially within the opening. An abrading unit is attachable to one end of said shaft while a desired weight i s' attachable at the other end; Thus when assembled upon a suitable stand, this apparatus maybe positioned with the lap of the abrading unit in contact with the surface to be tested. Sineethe shaft is axially free floating within the opening of the driving cam, the weight opposite the lap will .determinethe pressure exerted by the lap against the surface being tested. When the driving cam is rotated by a suitable power source about its center, the eccentric opening in the cam causes the lap to follow a circular path on the surface to be tested. The abroading unit w shaft or lap shaft also passes through an elongated slot in a guide plate slidably mounted for reciprocation along a line perpendicular to said slot. The portion of the shaft passing through the slot has opposed flattened faces engaging the lengthwise edges of said slot to prevent rotation of the shaft and its associated abrading unit. The combination of the circular motion applied by the driving cam to said shaft and abrading unit and the relation of the shaft to the plate preventing rotation of said shaft results in a circular abracling action being applied to the surface being tested, this action being the same as a persons hand when polishing or abrading 2 a surface with a circular motion, i. e. free of rotation.

To determine and record the number of cycles made by the abrading unit and its lap, a suitable and conventional counter is linked .to the plate. As the shaft follows the circular path imparted thereto by the cam it is free to more along the slot in the plate while the other componentof the circular motion is taken up by the recipe rocability of said plate along the line perpendicue lar to said slot. A suitable linkage connects this reciprocating plate to the .arm .of aconventional counter, thereby causing each motion of said plate in one direction, corresponding to each cycle of the abrading surface along its circular path, to register on the .counter.'

The above is a general description of the role, tions'hip of the essential elements of this novel abrasion testingapparatus; the following is a do.-

tailed description thereof 'made in conjunction with the attached drawings, wherein like nu.- merals in the several views. refer to the same or corresponding parts of the invention.

In the drawings:

Fig. l is a perspective view :of one embodiment of the present invention in inoperative position with the lap supporting arm lifted and swung to one side-and the ab-r-ad-ing unit removed to expose the workpiece;

Fig. 2 is a side elevation view of the embodiment illustrated in Fig: l in use with the lap lowered for cent-act with a work-piece;

Fig. 3 is a simplified vertical cross-section taken through the abraeling unit and its support but omitting certain ofthe' parts;

:Fig. 4 is an emer ed and exploded detailed isometric perspective'view of the abrading unit;

Fig. 5 is aperspective view of the guide plate;

fig. -6 a perspective -view of the eccentric cam; and 'i is :a perspective view of the abrading unit or lap shaft. The'base lil, '-formed of metal or other suitable structural and supporting nriafterial, supports stand H andhas leveling screws 12 positioned in a h corner er W e ongate slo s 3 are formed in said plate along one diagonal there'- 01 lmps M are iid ne i lslots nd at occupa ional clamp; nut a d b t arran ement for ngaging said. b se through said ots a d fix ng sa d c amps inaoiu ted positio i ra em nt thusl s vise. fo h lding theoloiect t h tested in position the base 10.

arm 80 which is vertically and pivotally adjustable thereon. The arm 80 carries the abrading unit and its shaft [6 and weight I1 associated therewith, the counter l8, the plate 19, and the cam 20.

Cam 20, shown in enlarged perspective View in Fig. 6, is a circular cylinder having at one end an outwardly extending annular flange 2| and an eccentric hole 26 therethrough. This cam is fitted into opening 22 of arm 80 which has at one end an inwardly extending annular shoulder 23. When the cam is inserted in this opening, flange 2| engages shoulder 23 while portion 24 depends from said arm. Pulley '25 is afiixed to this depending portion in any suitable manner, as by the application of a set screw as shown. Guide plate l9, shown in enlarged perspective view in Fig. 5, having an elongated slot 28v therethrough, is slidably mounted by means of brackets 29 on the arm 80 for reciprocation therealong. The abrading unit or lap shaft l6, shown in enlarged perspective View in Fig. '7, is vertically slidable in the hole 26 of the cam and may be restrained against rotation by engagement of its flattened faces 90 on portion 91 with the sides 92 of slot 28 in guide plate 19. A removable weight His secured to shaft H3 at its upper end by any conventional means such as being screwed thereon and jammed in position by a bolt 96, or fixed thereon by a set screw. It is by abutment of weight I! against plate l9 or its associated brackets that this shaft is kept from slipping through the openings in which it is positioned. The abrading unit [5 is detachably mounted on the other end of the shaft [6 by any conventional means such as screw, chuck, or friction.

A suitable bracket 38 is attached to arm 80 and carries a conventional counter 18 having an actuating lever 32. Post 33 mounted on plate I9 is linked to lever 32 by connecting rod 34, pivotally secured at opposite ends to the post and lever. This linkage is such as to cause the actuation of the counter on the completion of each reciprocation cycle of the plate l9. Since a reciprocation occursfor each rotation of cam 20, this provides a simple and positive means for indicating the completion of a cycle of the abrading unit.

. The abrading unit l5, the parts of which are shown in enlarged exploded views in Fig. 4, is constructed in the following manner: A conical section 40 having an annular flange 4| extending therefrom at its larger end has its smaller end 42 covered by a suitable cupped cloth 43, of broadcloth, soisette, percale, or similar material. The edge of the covering cloth is flanged to overlie flange 4|. An annular anchoring ring 44 is placed over the flanged portion of the cloth and has pins 45 projecting therefrom, passing through said cloth, and entering corresponding openings in the flange 4|. Flange 4! is further provided with external threads 48 for receiving the internally threaded clamping ring 46. Ring 46 has an inwardly projecting annular shoulder 41 at one end thereof, so when applied to the flange 4| and tightened thereon the shoulder 41 will abut the anchoring ring 44 forcing it into secure engagement with the cloth and the flange 4 I. The cupped cloth 43 forms the abrading surface or lap, performing its function in conjunction with a suitable abrasive such as powdered magnesium fluoride or the like.

The arm 80 is retained in vertically adjusted position by a split annular clamp or stop 50 having a thumb screw 5| therethrough for drawin said clamp tightly about the stand. Thus when clamped in position arm cannot slip below the stop. A spacing post "It is attached to the un; dersurface of arm 80 near stand H and is so placed as to be at all times located over said stop. Therefore, in the inoperative position of the device shown in Fig. 1, it is the abutment of the end of this post against the stop which limits the downward slipping of the arm. Stop 50 is provided with a hole 52 which receives the post T0 with a relatively snug fit. With the post inserted in said hole the apparatus is ready for operation, as shown in Fig. 2, the engagement of the post with. the hole 52 serving to retain the arm 80 in place against lateral movement.

In operation, power for the apparatus is afforded by a motor 60 or the like having a pulley Bl mounted thereon for driving a pulley belt 62. The pulley belt is connected to pulley 25 which causes the rotation of cam 20 in its seat in arm 80. The eccentric opening 26 in the cam is thus caused to follow a circular path. The shaft 16 and its attached abrading unit will likewise be caused'to travel a circular path over the surface being tested. The pivotability of the shaft IS in the opening 26 combined with the engagement of flat faces of the shaft with the lengthwise edges 92 of the slot 28 in plate l9 effectively eliminate any rotary action of the abrading unit with respect to the surface being tested which would otherwise be imparted thereto. Thereby, this apparatus performs an action the same as that of hand abrading when done with a cir-e cular motion.

Thus, with the object 95 whose surface is to be tested properly clamped in place by clamps l4, and with the stop 50 properly adjusted to bring the lap in contact with the surface of the object when post 1 is lowered into hole 52 to obtain the operative position of the apparatus, as shown in Fig. 2, the apparatus can be operated to performthe desired test for a determined number of abrading cycles. At the completion of the test, the arm 80 may be raised and swung into the inoperative position as shown in Fig. 1.

The above description of this device and its function is merely illustrative and is not intended to limit the invention to the exact disclosure. Modifications of this apparatus within the spirit and scope of this invention as defined by the following claims will be apparent to those skilled in the art.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. An abrasion resistance testing machine for testing by means of a circularly traveling abrading unit comprising a supporting structure, a. plate mounted for reciprocable movement thereon and having an elongated slot therein extendin'g transversely to the line of reciprocation, a cam carried by said structure, said cam having an eccentric opening therein, a lap shaft passing through said eccentric opening and said elongated slot, said shaft being freely slidable through said opening, and said shaft and cam being relatively rotatable with respect to each other, said shaft having a flattened side portion for engagement with a side of said slot permitting free sliding of said shaft therethrough and therealong while restraining axial rotation of said shaft, a weight carried by said shaft, and means for rotating said cam, the rotation of said cam causing a circular motion of the lap shaft, said' slotted plate preventing axial rotation thereof, and said weight affording a desired abrading pressure.

2. An abrasion resistance testing machine comprising a supporting structure, a plate slidably mounted thereon for reciprocable movement and having an elongated slot therein substantially transverse to the line of reciprocation, a cam carried by said structure, said cam having an eccentric opening therein, a lap shaft passing through said eccentric opening and said elongated slot, said shaft and cam being relatively rotatable, said shaft having a flattened side portion engaging an edge of said slot for restraining rotation of said shaft, the rotation of said cam causing a circular motion of the shaft by means of the eccentric opening therein, but said slotted plate preventing rotation thereof.

3. A device of the type described comprising a reciprocably mounted plate having a slot therein extending substantially transversely to the line of reciprocation, a lap shaft extending through said slot and being restrained against axial rotation by cooperation between said shaft and said plate, rotatable means for driving said shaft in a circular path, said shaft being freely retained by said driving means to enable relative rotational movement therebetween, and pressure means applied to said shaft for affording a desired abrading or polishing pressure.

4. A device of the type described comprising a lap shaft, a rotatable means for driving said shaft in a substantially circular path and freely retaining said shaft for relative rotational movement therebetween, means cooperating with a portion of said shaft for restraining it against axial rotation but said shaft being free for longitudinal movement relative to said rotation restraining means, thereby providing a free floating lap shaft for circular motion free of rotational motion, and variable pressure means applied to said lap shaft for affording a desired abrading or polishing pressure.

5. A device of the type described comprising a reciprocably mounted plate having a slot therein extending substantially transversely to the line of reciprocation, a lap shaft extending through said slot and having a flattened side portion for engaging an edge of said slot, and rotatable means for imparting a circular motion to said shaft by reciprocating said plate on said supporting structure and reciprocating said shaft along said slot, cooperation between said fiattened side portion of said shaft and said plate through said slot restraining said shaft against rotation about its longitudinal axis.

6. A device for translating rotary motion to circular motion comprising a shaft, rotatable means for driving said shaft in a circular path, said shaft being retained by said driving means with free relative rotational movement therebetween, a reciprocably mounted plate having an elongated slot therein extending substantially transversely to the line of reciprocation, said shaft passing through said slot and cooperating with said plate to restrain rotation of said shaft, the rotation of said driving means imparting a circular motion to said shaft by movement thereof along said slot and by reciprocation of said plate but said plate preventing rotation of said shaft.

DONALD M. PACKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 157,261 Wood Nov. 24, 1874 2,195,065 Wallace Mar. 26, 1940 2,412,221 Kallas et al. Dec. 10, 1946 

